On the virtual aeroshaping effect of synthetic jets

Mittal, Rajat; Rampunggoon, P.

doi:10.1063/1.1453470

Cited by 156 publications

(70 citation statements)

References 18 publications

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“…• Main (primary) flow control (jet vectoring [5,6], flow field control in external or internal aerodynamics [7], increasing heat transfer due to the main flow control [8,9]). • The use of a stand-alone SJ or system of synthetic jets (SJ used for intensification of heat transfer [10,11].…”

Section: Synthetic Jetmentioning

confidence: 99%

Experimental Investigation of a Synthetic Jet Array in a Laminar Channel Flow

Dančová

Trávníček

Vít

2013

EPJ Web of Conferences

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Abstract. The paper deals with an impinging synthetic jet, namely on the case of a synthetic jet array interacting with a laminar channel flow. This arrangement can be useful in many micro-scale applications, such as cooling of micro-electronics. The flow regime in micro-scale is usually laminar with very small Reynolds numbers; therefore synthetic jet array can be used for the profile disturbance and heat transfer enhancement. The paper focuses on the low Reynolds number (in order 10 2 ). The working fluid is water and a piezoceramic transducer is used as a moving membrane in the synthetic jet actuator. Experiments are performed with four experimental methods (tin ion visualization, hot wire anemometry in constant temperature mode, laser Doppler vibrometry and particle image velocimetry) in three laboratories (at the Eindhoven University of Technology, Netherlands, at the Institute of Thermodynamics CAS, v.v.i. and Technical University of Liberec, both Czech Republic).

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Section: Synthetic Jetmentioning

confidence: 99%

Experimental Investigation of a Synthetic Jet Array in a Laminar Channel Flow

Dančová

Trávníček

Vít

2013

EPJ Web of Conferences

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“…A large operational difference between continuous and synthetic jets is that the latter do not need an external fluid supply and therefore can be easily integrated in complex geometries, making them attractive actuators for flow control. Applications of synthetic jets, such as separation control (Dandois et al 2007), turbulent boundary layer control (Rathnasingham & Breuer 2003;Canton et al 2016), virtual aeroshaping (Mittal & Rampunggoon 2002), thrust vectoring (Smith & Glezer 2002;Luo & Xia 2005), heat transfer (Persoons et al 2009) or propulsion (Athanassiadis & Hart 2016), include, but are not limited to, applications with a crossflow. For most of these applications, the specific direction of the synthetic jet is important.…”

Section: Introductionmentioning

confidence: 99%

Vectoring of parallel synthetic jets: a parametric study

2016

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The vectoring of a pair of parallel synthetic jets can be described using five dimensionless parameters: the aspect ratio of the slots, the Strouhal number, the Reynolds number, the phase difference between the jets and the spacing between the slots. In the present study, the influence of the latter four on the vectoring behaviour of the jets is examined experimentally, using particle image velocimetry. Time-averaged velocity maps are used to give a qualitative description of the variations in vectoring for a parametric sweep of each of the four parameters independently. A diverse set of vectoring behaviour is observed in which the resulting jet can be merged or bifurcated and either vectored towards the actuator leading in phase or the actuator lagging in phase. Three performance metrics are defined to give a quantitative description of the vectoring behaviour: the included angle between bifurcated branches, the vectoring angle of the total flow and the normalized momentum flux of the flow. Using these metrics, the influence of changes in the Strouhal number, Reynolds number, phase difference and spacing are quantified. Phase-locked maps of the swirling strength are used to track vortex pairs. Vortex trajectories are used to define three Strouhal number regimes for the vectoring behaviour. In the first regime, vectoring behaviour is dominated by the pinch-off time, which is written as function of Strouhal number only. In the second regime, the pinch-off time is invariant and the vectoring behaviour slightly changes with Strouhal number. In the third regime, given by the formation criterion, no synthetic jet is formed. Vortex positions at a single phase, shortly after creation of the lagging vortex pair, are used to propose a vectoring mechanism. This vectoring mechanism explains the observed qualitative and quantitative variations for all four parameters.

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“…It has emerged as a versatile actuator with potential applications ranging from separation and turbulence control to thrust vectoring, and augmentation of heat transfer and mixing [ [3], [8], [12], [16], [30]]. A unique feature of synthetic jets is that they are formed entirely from the working fluid of baseline flow without requirement of additional mass supply [[6]].…”

Section: Synthetic Jet Actuatormentioning

confidence: 99%

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient

2010

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In the development of synthetic jet actuators (SJAs) for active flow control, numerical simulation has played an important role. In controlling the boundary layer flow separation, an integrated numerical model which includes both the baseline flow and the SJA is still in its initial stage of development. This paper reports preliminary results of simulating the interaction between a synthetic jet and a laminar separation bubble caused by adverse pressure gradient in a boundary layer. The computational domain was three-dimensional and Large-eddy simulation (LES) was adopted. The initial and boundary conditions were defined using or referring to our wind tunnel experimental results. Prior to numerically simulating the interaction between the synthetic jets and the baseline flow, a numerical model for simulating the separation bubble was developed and verified. In the numerical model including the SJA, the synthetic jet velocity at the exit of the SJA was defined as an input. The numerical model was further verified by comparing the simulation with experimental results. Based on reasonable agreement between the numerical and experimental results, simulations were carried out to investigate the dependency of flow control using synthetic jets on the forcing frequency, focused on the lower frequency range of the Tollmien-Schlichting (T-S) instability, and on the forcing amplitude which was represented by the maximum jet velocity at the exit of the SJA. Supporting the hypothesis based on the 1 experiment, LES results showed that the forcing frequency had stronger influence on SJA's effective elimination of the separation bubble than the forcing amplitude did.Key words: synthetic jet actuator, micro sensor, numerical modeling, flow control.

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On the virtual aeroshaping effect of synthetic jets

Cited by 156 publications

References 18 publications

Experimental Investigation of a Synthetic Jet Array in a Laminar Channel Flow

Experimental Investigation of a Synthetic Jet Array in a Laminar Channel Flow

Vectoring of parallel synthetic jets: a parametric study

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient

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